A Jewish official who is a close political associate of New Jersey Gov. Chris Christie repeatedly invoked the Fifth Amendment and refused to answer questions at a state legislative hearing into a decision to close lanes on the George Washington Bridge as a political attack on a Democratic mayor.

David Wildstein, a longtime Republican operative who went to high school with Christie, repeatedly invoking the constitutional protection not to say anything that might incriminate himself at the Trenton hearing.

Wildstein has admitted ordering the lane closures and recently resigned his post at the Port Authority, a quasi governmental body that oversees New York metro bridges and tunnels.

Damaging emails in the scandal were supplied to the media by Wildstein in response to a subpoena issued by a panel of state lawmakers.

Hoping to quell the furor over the scandal, Christie dismissed his deputy chief of staff, Bridget Anne Kelly, whose role emerged in the emails.

In the most damning email, Kelly wrote to Wildstein in August, saying: “Time for some traffic problems in Fort Lee.”

Wildstein, replied: “Got it.”

Christie on Thursday claimed he had been blindsided in the scandal that has tarnished his political reputation on the national stage.

He also sought to distance himself from Wildstein, who went to the same high school in the town of Livingston as the governor and is widely viewed as a Christie apparatchik.

“David and I were not friends in high school,” Chirstie said. “We were not even acquaintances in high school.”

“We went 23 years without seeing each other,” Christie added. “And in the years we did see each other, we passed in the hallways. I want to clear that up.”

As Christie apologized publicly for the abrupt lane closings ordered by some of his staff, which he said he did not know about beforehand, the office of the U.S. Attorney in New Jersey said it was launching an investigation.

Revelations that his staff plotted the four-day lane closures at the George Washington Bridge in September, causing hours-long traffic jams that stalled commuters, school buses and ambulances, come as Christie has emerged as a powerful figure in the Republican Party and a possible presidential contender.

The controversy erupted with the release on Wednesday of incriminating emails showing Christie’s aide and allies planning the lane closings to punish the Democratic mayor of Fort Lee, at the New Jersey end of the bridge, because he had declined to endorse Christie’s re-election effort.

“I am embarrassed and humiliated by the conduct of some of the people on my team,” Christie said. “I am who I am, but I am not a bully.”

As the head of the party’s governors association and a possible 2016 White House contender, the tough-talking governor has sought to present himself as a leader who can work with opponents and forge bipartisan alliances.

U.S. Attorney Paul Fishman, whose job Christie held before being elected governor, has opened a probe, his spokeswoman said.

“Our office is reviewing it to determine whether a federal law was implicated,” Rebekah Carmichael said in a statement.

A local newspaper reported emergency responders were delayed in attending to four medical situations - one involving an unconscious 91-year-old woman who later died of cardiac arrest and another, a car accident, in which four people were injured.

At the news conference, Christie referred to the lane closings as a “rogue political operation.”

“I am stunned by the abject stupidity that was shown here,” Christie said. “This was handled in a callous and indifferent way, and this is not the way this administration has conducted itself over the last four years.”

Christie took reporters’ questions at the packed news conference at his office that lasted just short of two hours.

He appeared contrite, describing himself repeatedly as heartbroken and apologizing to the public, and even to the media, several times.

Toward the end of his lengthy appearance, he visibly relaxed, leaning against the podium, and resorted to his more typical form, calling one reporter’s question “crazy.”

Christie has enjoyed immense popularity at home since his election in 2009, particularly for his handling of recovery and rebuilding efforts after Superstorm Sandy devastated his state in late 2012. He was re-elected in a landslide in November.

But he is known as well for engaging in shouting matches, hurling insults and belittling challengers.

Political observers said at first glance that Christie’s response to the scandal achieved what he set out to do.

“He did well, in that he offered an aggressive response. He showed the personality that people like - which is the person who seems to like to be right in the middle of things, even in a scandal situation like this,” said Julian Zelizer, a Princeton University professor of history and public affairs.

“At least for now, he offered the thing that was most important here - that he was going to hold people responsible.”